Vehicle seat assembly having a cradle seat back

ABSTRACT

A seat assembly for supporting a seat occupant in an automotive vehicle comprising a seat cushion for support the seat occupant on the seat assembly ( 10 ) and a seat back ( 16 ) extending longitudinally between a lower portion operatively coupled to the seat cushion and an upper portion for supporting the seat occupant in an upright position. The seat back ( 16 ) includes an outer peripheral frame member and an inner occupant support frame operatively connected and supported by the outer peripheral frame member and movable from an occupant support position to an impact displacement position extending rearwardly of the outer peripheral frame member. A displaceable connection member operatively interconnects the inner occupant support frame in the occupant support position during normal seat occupant use and for providing movement of the inner occupant support frame to the impact displacement position in response to a predetermined impact load exerted on the seat assembly ( 10 ).

BACKGROUND OF THE INVENTION

1. Field of Invention

The present invention relates generally to a seat assembly for use in anautomotive vehicle, and more particularly, to a seat assembly having aninner occupant support frame which is movable from an occupant supportposition to an impact displacement position in response to rear impactloads on the seat assembly.

2. Description of the Related Art

Automotive vehicles include seat assemblies for supporting driver andpassenger occupants within the vehicle. These seat assemblies include agenerally horizontal seat cushion and an upright seat back. The seatback is commonly operatively coupled to the seat cushion by a reclinermechanism for providing pivotal adjustment of the seat back relative tothe seat cushion between an upright seating position and a plurality ofreclined positions. The vehicle also includes a seat restraint systemoperable with the seat assembly for maintaining the seat occupant in theseat upon the incident of a sudden impact upon the vehicle.

It is becoming increasing desirable to provide additional safetyfeatures within the vehicle and on the seat assembly for safelyrestraining the occupant in the seat and absorbing energy within thevehicle upon impact.

For example, the seat assembly often includes a head restraint connectedto the upper portion of the seat back for protecting the occupant's headduring a vehicle accident. Head restraint may be vertically adjustableto accommodate various occupant heights and pivotally adjustable toposition the head restraint close to the occupant head to assist inprevent “whiplash” upon vehicle impact. The U.S. Pat. No. 5,378,043 toViano et al. discloses a head restraint which is pivotally coupled tothe seat back whereby upon a rear vehicle impact the head restraintmoves in a forward direction toward the head of the seat occupant.

Seat assemblies may also include displacable seat mechanisms fordisplacing the entire seat assembly, or the entire seat back, rearwardlyupon rear vehicle impact to maintain the occupant in the seat and absorbenergy via the movement of the seat. Examples of displacable and energyabsorbing seat assemblies are disclosed in U.S. Pat. Nos. 6,050,637;6,109,692 and 6,062,642.

It remains desirable, however, to improve the retention and energydissipation in a seat assembly to protect an occupant during a vehiclerear impact.

SUMMARY OF THE INVENTION

The present invention relates to a seat assembly for supporting a seatoccupant in an automotive vehicle comprising a seat cushion for supportthe seat occupant on the seat assembly and a seat back extendinglongitudinally between a lower portion operatively coupled to the seatcushion and an upper portion for supporting the seat occupant in anupright position. The seat back includes an outer peripheral framemember, an inner occupant support frame operatively connected andsupported by the outer peripheral frame member and movable from anoccupant support position to an impact displacement position extendingrearwardly of the outer peripheral frame member, and a displacableconnection member operatively connecting the inner occupant supportframe and the outer peripheral frame for maintaining the inner occupantsupport frame in the occupant support position during normal seatoccupant use and for providing movement of the inner occupant supportframe to the impact displacement position in response to a predeterminedimpact load exerted on the seat assembly.

BRIEF DESCRIPTION OF THE DRAWINGS

Other advantages of the present invention will be readily appreciated asthe same becomes better understood by reference to the followingdetailed description when considered connection with the accompanyingdrawings wherein:

FIG. 1 is a front view of a seat assembly according to the presentinvention;

FIG. 2 is a perspective view of the seat assembly of FIG. 1;

FIG. 3 is a perspective view of a linear recliner operatively coupledbetween a seat back and seat cushion of the seat assembly of FIG. 1;

FIG. 4 is a perspective view of an inner occupant support frame of theseat assembly of FIG. 1;

FIG. 5 is a perspective view of a pivot bracket for pivotally attachinga head restraint to the seat back of the seat assembly;

FIG. 6 is a cross-sectional side view of the pivot bracket pivotallyattaching the head restraint to the seat back;

FIG. 7 is a side view of an adjustable lumbar support assemblyoperatively connected to the inner occupant support frame;

FIG. 8 is a perspective view of a lower portion of the linear reclinerpivotally attached to the seat cushion;

FIG. 9 is a perspective view of an upper portion of the linear reclinerpivotally attached to the seat back;

FIG. 10 is an alternative embodiment of a linear recliner for attachmentbetween a seat cushion and a seat back;

FIG. 11 is yet another alternative embodiment of a linear recliner forattachment between a seat cushion and a seat back;

FIG. 12 is a side view of the seat assembly;

FIG. 13 is a side view of the seat assembly showing the inner occupantsupport frame in an occupant support position and an impact displacementposition;

FIG. 14 is a perspective view of an alternative embodiment of a seatassembly and an inner occupant support frame;

FIG. 15 is a perspective view of a displacable connection member of theseat assembly of FIG. 14 for providing movement of the inner occupantsupport frame from an occupant support position to an impactdisplacement position;

FIG. 16 is a front view of another alternative embodiment of a seatassembly and an inner occupant support frame;

FIG. 17 is a front view of yet another alternative embodiment of a seatassembly and an inner occupant support frame;

FIG. 18 is a front view of still another alternative embodiment of aseat assembly and an inner occupant support frame.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring to FIGS. 1-3, a seat assembly is generally depicted at 10 forsupporting a seat occupant in an automotive vehicle, simulated at 12.The seat assembly 10 includes a generally horizontal seat cushion 14 forsupporting the seat occupant on the seat assembly 10 and a seat back 16extending longitudinally between a lower portion 18 operatively coupledto the seat cushion 14 and an upper portion 20. The seat cushion 14includes a tubular seat cushion frame 22 forming a rigid and generallyrectangular support frame having a first cross bar member 24 adjacent tothe lower portion 18 of the seat back 16 and an opposing second crossbar member 26 spaced forwardly of the first cross bar member 24. Theseat cushion frame 22 further includes spaced apart and opposing inboardand outboard support bar members 28, 30 which extend between the firstand second cross bar members 24, 26. A flexible membrane suspension mat32 is supported between the inboard and outboard support bar members 28,30 by a plurality of hooks or connecting links 34 for supporting theseat occupant on the seat assembly 10 as is commonly known in the art.

The seat cushion frame 22 is supported on a conventional seat trackassembly 36 which extends longitudinally between the first cross barmember 24 and the second cross bar member 26 for providing fore and aftmovement of the seat assembly 10 in the vehicle 12, as is commonly knownin the art. The seat track assembly 36 includes an inboard and outboardupper track 38, 40 slidably coupled to respective inboard and outboardlower tracks 42, 44. A pair of front brackets 46, 48 fixedly secure therespective inboard and outboard support bar members 28, 30 of the seatcushion frame 22 to the respective upper tracks 38, 40 adjacent to thesecond cross bar member 26. Similarly, a pair of U-shaped rear brackets50, 52 fixedly secure the respective inboard and outboard support barmembers 28, 30 to the respective upper tracks 38, 40 adjacent the firstcross bar member 24.

Referring to FIGS. 1 and 3, the seat track assembly 36, and thus, theentire seat assembly 10 is mounted to and between longitudinalstructural elements typically referred to as the central tunnel 54 andoutboard sill 56 and supported above the vehicle floor, illustrated at58, by a pair of support bars 60, 62 which extend laterally between theopposing tunnel 54 and sill 56. More specifically, the lower tracks 42,44 are mounted and secured to each of the support bars 60, 62 betweenthe tunnel 54 and sill 56. The supporting of the seat assembly 10 abovethe vehicle floor 58 provides space below the seat cushion 14 foradditional storage within the vehicle 12 and additional foot room for avehicle occupant seated behind the seat assembly 10. The outboard, andpotentially exposed, ends of the support bars 60, 62 may be covered andintegrated with the sill of the vehicle by being trimmed by floorcovering 64 to match the vehicle floor 58.

Referring to FIGS. 1-4, the seat back 16 includes a rigid, tubular,outer peripheral frame member 66 forming a generally U-shaped seat backframe. The outer peripheral frame member 66 includes a pair of spacedapart inboard and outboard side support bars 68, 70 extendinglongitudinally from a first distal end 72 adjacent the seat cushion 14and a second end 73 to define a seat occupant back support envelopetherebetween. An upper support bar 75 interconnects the second ends 73of the side support bars 68, 70. The first distal ends 72 of each of theinboard and outboard side support bars 68, 70 are pivotally attached tothe respective inboard and outboard rear brackets 50, 52 via pivot pins77 to provide pivotal reclining movement of the seat back 16 withrespect to the seat cushion 14. A rigid support brace 79 furtherinterconnects the inboard and outboard side support bars 68, 70 midwaybetween the first distal ends 72 and the second ends 73 to provideadditional structural rigidity to the outer peripheral frame member 66.

Referring to FIGS. 1-4 and 8-9, the seat assembly 10 further includes apair of linear recliner mechanisms 74, 76 coupled between the seatcushion 14 and seat back 16 for selectively adjusting the seat back 16between a range of angular reclined positions relative to the seatcushion 14. More specifically, each linear recliner mechanism 74, 76includes an upper cylinder 78 having a first end pivotally attached bypivot pin 80 to a bracket 82 on each respective inboard and outboardside support bar 68, 70 of the outer peripheral frame 66, as shown inFIG. 9, and a second open end. The linear recliner mechanisms 74, 76also include a lower piston 84 having a first end telescopingly receivedin the open end of the upper cylinder 78 and a second end pivotallyattached by pivot pin 86 to the respective rear brackets 50, 52 on theseat cushion frame 22. The second end of the lower piston 84 is spacedforward of the pivot pin 72 connecting the outer peripheral frame 66 ofthe seat back 16 and the seat cushion frame 22 to complete atriangulated structural frame between the outer peripheral frame 66, theseat cushion frame 22 and the linear recliner mechanisms 74, 76. Thesecond end of the lower pistons 84 and the pivot pins 86 are covered bya tubular trim fairing 87. Referring to FIG. 5, each linear reclinermechanism 74, 76 includes a spring bias locking mechanism 88 secured tothe upper cylinder 78 and engagable with the lower piston 84 for lockingand retaining the linear recliner mechanism 74, 76 within the range ofreclined positions. A Bowden-type cable assembly 90 is interconnectedbetween the locking mechanism 88 and a release latch 92 for releasingthe locking mechanism 88 and allowing the pivotal movement of the seatback 16 to a desired reclined position. The seat back 16 is biasedtoward a generally upright position as shown in FIGS. 1-4 by a pair oftension springs 94, 96 extending between the seat back 16 and the seatcushion 14 adjacent to and inward of the respective linear reclinermechanism 74, 76. More specifically, referring to FIGS. 8 and 9, eachtension spring 94, 96 has a first end 98 connected to the bracket 82 anda second end 100 connected to the respective rear bracket 50, 52. Thesprings 94, 96 are pulled in tension as the linear recliner mechanisms74, 76 are released and the seat back 16 is pivoted to a reclinedposition by the seat occupant. Therefore, when the linear reclinermechanisms 74, 76 are released, the seat back 16 is automatically biasedtoward the generally upright position.

Referring to FIG. 10, an alternative embodiment of a linear reclinermechanism 74 is shown including a tension spring 94 extending betweenthe first end of the upper cylinder 78 and the second end of the lowerpiston 84. The tension spring 94 includes a first coil portion 102spiraled around the second end of the lower piston 84 and a second coilportion 104 spiraled around the first end of the lower piston 84. Thefirst and second coil portions 102, 104 are joined by a straight torsionbar section 106 seated between the upper cylinder 78 and the lowerpiston 84.

Referring to FIG. 11, another alternative embodiment of a linearrecliner mechanism 74 is shown including a tension spring 94 extendingbetween the first end of the upper cylinder 78 and the second end of thelower piston 84. The tension spring 94 includes a coil portion 102spiraled around a portion of the lower piston 84 adjacent the second endand a straight torsion bar section 106 extending from the first end ofthe upper cylinder 78 and the coil portion 102 and seated between theupper cylinder 78 and the lower piston 84.

Referring again to FIGS. 1, 2, 5 and 6, the seat assembly 10 furtherincludes a head restraint 108 operatively connected to the seat back 16.The head restraint 108 includes a generally U-shaped frame member 110having a tubular, rod or wire construction and defined by a pair ofspaced apart head restraint posts 112 and an upper arc portion 114. Theupper arc portion 114 maybe trimmed by a foam pad and trim cover, ascommonly known in the art, and including a center head restraint panelof a transparent material to provide rear view visibility to a frontseat occupant. The posts 112 extend from the arc portion 114 above theupper support bar 75 to a distal end 116 spaced below the upper supportbar 75. Each of the posts 112 are pivotally attached to the uppersupport bar 75 by a pivot bracket 118. Referring specifically to FIGS. 5and 6, the pivot bracket 118 includes a first plate 120 having asemi-cylindrical base portion 122 in mating engagement with the uppersupport bar 75 and a second plate 124 having a semi-cylindrical baseportion 126 in mating engagement with the upper support bar 75, oppositethe semi-cylindrical base portion 122, and encapsulating a portion ofthe upper support bar 75 therebetween. The second plate 124 is fastenedto the first plate 120 by a bolt 128 to provide frictional resistancebetween the plates 120, 124 and the upper support bar 75 while allowingrotation of the plates 120, 124 around the upper support bar 75. Thefirst plate 120 further includes a pair of spaced apart parallel upperand lower flanges 130, 132 extending outwardly from the semi-cylindricalbase portion 122. Each of the flanges 130, 132 includes a through hole134, 136 for receiving one of the head restraint posts 112 and fixedlysecuring the head restraint frame member 110 to the pivot brackets 118,and thus, the upper support bar 75. The pivot brackets 118 providefrictional resistance and pivotal movement of the head restraint framemember 110 about the upper support bar 75 to support the seat occupant'shead, as will be described in more detail herein below.

The distal ends 116 of the head restraint posts 112 are interconnectedby an upper seat back support plate 138 which extends laterally betweenthe inboard and outboard side supports bars 68, 70 below the uppersupport bar 75. The upper seat back support plate 138 pivots the headrestraint 108 forwardly toward the seat cushion 14 and about the uppersupport bar 75 in response to a force F being applied to the seat back16 and upper seat back support plate as shown in FIG. 6. The forwardpivoting of the head restraint 108 positions the head restraintimmediately adjacent the seat occupants head to absorb energy in a rearimpact vehicle collision as will be discussed in greater detail below.

Referring to FIGS. 1, 2, and 4, the seat assembly 10 further includes aninner occupant support frame 140 operatively connected and supported bythe outer peripheral frame 66 and movable from an occupant supportposition to an impact displacement position extending rearwardly of theouter peripheral frame 66. The inner occupant support frame 140 ismounted on a lateral torsion spring element 141 forming spring coils 147connected to the first distal ends 72 of the respective inboard andoutboard side support bar 68, 70 of the outer peripheral frame 66. Thetorsion spring element 141 includes a pair of spaced apart torsion bars142, 144 extend upwardly from the first distal end 72 to a torso supportbar 146 adjacent the respective inboard and outboard side support bars68, 70. The torso support bar 146 extends laterally between the opposinginboard and outboard side support bars 68,70 and is positioned betweenthe support brace 79 and the seat cushion 14 and slightly rearward ofthe outer peripheral frame 66. In the embodiment of FIGS. 1-4, the inneroccupant support frame 140 further includes a pair of elastic straps148, 150 extending parallel to the inboard and outboard side supportbars 68, 70 between the torso support bar 146 and the upper support bar75. More specifically, the elastic straps 148, 150 include a first end152 connected to the torso support bar 146 adjacent the respectivetorsion bar 142, 144 and a second end 154 connected to the respectivepivot bracket 118 of the head restraint 108. Additionally, the upperseat back support plate 138 is positioned forward of the elastic straps148, 150 and may be operatively connected thereto by the straps 148, 150passing through a slot in each opposing ends of the support plate 138.

Referring to FIGS. 1, 4 and 7, the inner occupant support frame 140further includes a four-way adjustable lumbar support assembly 156. Thelumbar support assembly 156 includes a generally rectangular and planarsupport plate 158 having a longitudinally extending U-shaped channel 160for receiving the torso support bar 146 therein and securing the supportplate 158 to the torso support bar 146. A plurality of air bladders 162are connected to the support plate 158 and in fluid communication viaair lines 164 with a pneumatic actuator 166. The pneumatic actuator 166is secured to the second, or front, cross bar member 26 of the seatcushion frame 22 and operatively connected to an electro-pneumaticcontroller 168 secured to the outboard support bar member 30. Acontoured lumbar back plate 170 is secured to the air bladders 162 via apair of rivets 172 to provide angular displacement relative to the fixedsupport plate 158. The controller 168 actuates the pneumatic actuator166 to pump fluid, in the preferred embodiment air, through the airlines 164 to the plurality of air bladders 162 and adjust thedisplacement of the lumbar back plate 170 for occupant comfort. Furtherdisclosure and operation of the lumbar support assembly 156 is fully setforth and described in U.S. Pat. No. 5,137,329, which is incorporatedherein by reference.

In operation, the inner occupant support frame 140 is displacablerelative to the outer peripheral frame 66 from the occupant supportposition during normal seat occupant use to an impact displacementposition in response to a predetermined impact load exerted on the seatassembly 10. More specifically, referring to FIG. 12, the seat assemblyand inner occupant support frame 140 are shown in the occupant supportposition. The seat occupant is supported on the seat cushion 14 and theseat back 16. The seat occupant's body, or torso, is supported by thelumbar support assembly 156 and the upper seat back support plate 138 inthe occupant support position with the head restraint 108 in a generallyupright position as shown in FIG. 12. Referring to FIG. 13, when apredetermined rear impact force F is exerted on the seat assembly 10,the seat occupant is forced against the seat back 16. The seat occupantexerts a force against the upper seat back support plate 138 which isconnected to the frame member 110 of the head restraint 108. Thus, theimpact force on the upper seat back support plate 138 pivots, orrotates, the frame member 110 about the pivot brackets 118 forwardlytoward the seat cushion 14 to close the distance between the headrestraint 108 and the seat occupant's head to protect the seat occupantand absorb impact forces. Further, the seat occupant also exerts a forceagainst the lumbar support assembly 156 which is supported by the inneroccupant support frame 140. The elastic straps 148, 150 allow the inneroccupant support frame 140 to move, or displace, rearwardly away fromthe outer peripheral frame 66, as shown in FIG. 13, to absorb the rearimpact forces exerted on the seat 10. The torsion bars 142, 144 and thetorso support bar 146 pivot against the spring bias force of the springcoils 147 and elastic straps 148, 150. Additionally, the seat occupantis displaced within the perimeter of the seat back outer peripheralframe 66 which provides a roll-bar type protective structure around thetorso of the seat occupant. Therefore, the seat back 16, including therigid outer peripheral frame 66 and the displacable inner occupantsupport frame 140 define a cradle about the seat occupant's torsoabsorbing the rear impact forces exerted on the seat 10. The springcoils 147 automatically return the inner occupant support frame 140 fromthe impact displacement position to the seat occupant position and theelastic straps 148, 150, which are coupled to the upper seat backsupport plate 138, return the head restraint 108 to the generallyupright position.

Referring to FIGS. 14 and 15, an alternative embodiment of a seatassembly 10, and more particularly, an inner occupant support frame 140is shown. The seat assembly 10 includes a seat back 16 having an outerperipheral frame 66 pivotally connected to a seat cushion frame 22. Ahead restraint assembly 108 is pivotally attached to the outerperipheral frame 66 as in the prior embodiment. The seat assembly 10also includes an inner occupant support frame 140 operatively connectedto the outer peripheral frame 66. The inner occupant support frame 140similarly includes a torsion spring element 141 including a pair oftorsion bars 142, 144 connected to the outer peripheral frame 66 byspring coils 147 and laterally interconnected by a torso support bar146. The torso support bar 146 supports a four-way pneumatic lumbarsupport assembly 156 as previously described. The inner occupant supportframe 140 further includes a pair of longitudinally extending wire rods180, as opposed to the elastic straps 148, 150, extending between therespective pivot brackets 118 and the torso support bar 146 adjacent therespective torsion bar 142, 144. The wire rods 180 include a first endconnected to the pivot brackets 118 and a second end forming a U-shapedhook 182 operatively connected to the torso support bar 146. The wirerods 180, and specifically the hooks 182, are connected to the torsosupport bar 146 by a displacable connection member 184. Theinterconnection between the wire rods 180 and the torso support bar 146by the displacable connection member 184 is best shown in FIG. 15. Thedisplacable connection member 184 includes a cylindrical body portion186 having a first channel 188 extending longitudinally between opposingends of the body portion 186 and a second channel 190 crossingtransverse to the first channel 188 and extending longitudinally betweenopposing ends of the body portion 186. The channels 188, 190 eachinclude a shelf 192, 194, respectively, for closing a portion of thechannel 188, 190 which is fracturable in response to a predeterminedload force. The displacable connection member 184 is positioned, orseated, between the hook 182 of each wire rod 180 and the torso supportbar 146. More specifically, the hook 182 is seated within the firstchannel 188 and supported by the shelf 192 and the torso support bar 146is seated within the second channel 190 and supported by the shelf 194.As shown in FIG. 15, the displacable connection member 184 maintains aspace between the torso support bar 146 and the hook 182 approximatelyequivalent to the longitudinal length of the member 184.

In operation, when a predetermined rear impact load is exerted on theseat assembly 10, a seat occupant force is exerted on the inner occupantsupport frame 140. The shelves 192, 194 fracture in response to apredetermined load allowing the respective hooks 182 and torso supportbar 146 to slide, or travel along their respective channels 188, 190until the hooks 182 engage with the torso support bar 146. The springcoils 147 allow the torsion bars 142, 144′ and torso support bar 146 topivot rearwardly behind the outer peripheral frame 66 while the wirerods 180 pivot with respect to the pivot brackets 118 forming a cradlebetween the outer peripheral frame 66 to secure and support the seatoccupant. The head restraint 108 operates independent of the inneroccupant support frame 140, however, also still rotates against thefrictional force of the pivot brackets 118 to support the seatoccupant's head.

FIG. 16 shows yet another alternative embodiment of a seat assembly 10and inner occupant support frame 140. The inner occupant support frame140 of the alternative embodiment of FIG. 16 includes the wire rods 180having the first end pivotally connected to the upper seat back supportplate 138 of the head restraint 108 and a second end forming a U-shapedhook 182 operatively connected to the torso support bar 146 bydisplacable connection members 184. In this embodiment, the displacementof the inner occupant support frame 140 also automatically rotates, orarticulates, the head restraint 108 about the pivot brackets 118 tosupport the seat occupant's head. Therefore, the head restraint 108 andthe inner occupant support frame 140 simultaneously displace from thenormal seating position and generally upright position to the impactdisplacement position in response to the predetermined rear impact loadon the seat assembly 10.

FIG. 17 discloses still another alternative embodiment of a seatassembly 10 and inner occupant support frame 140. The inner occupantsupport frame 140 includes a pair of generally U-shaped side supportrods 200 extending laterally between each of the respective inboard andoutboard side support bars 68, 70 of the outer peripheral frame 66 andthe lumbar support assembly 156. The support rods 200 include a pair ofspaced apart lateral rods 204, 206 extending from the respective inboardand outboard side support bars 68, 70 and interconnected by a verticalbar member 202 connected to the center portion of the lumbar supportassembly 156. The side support rods 200 pivot about the inboard andoutboard side support bars 68, 70 in response to the predetermined rearimpact force on the seat assembly 10 and inner occupant support frame140 to cradle the seat occupant between the outer peripheral frame 66. Abreak away displacable connection member 184 interconnects the verticalbar member 202 and the lower lateral rods 206 of the support rods 200such that when an impact load is exerted upon the seat 10 beyond adesignated load, the connection member 184 releases the vertical bar 202and allows the lower lateral rods 206 to straighten, thereby providingrearward displacement of the inner occupant support frame 140.

Finally, FIG. 18 discloses yet another alternative embodiment of a seatassembly 10 and inner occupant support frame 140. The inner occupantsupport frame 140 again includes a pair of generally rectangular sidesupport rods 210 extending laterally between each of the respectiveinboard and outboard side support bars 68, 70 of the outer peripheralframe 66 and the lumbar support assembly 156. The side support rods 210include a pair of spaced apart rods 212, 214 interconnected at a firstend by a cross bar member 216 and interconnected at an opposite secondend by a bolster support rod 218. The cross bar members 216 areoperatively connected to the adjacent sides of the lumbar supportassembly 156 and the second ends of the lateral rods 212, 214 arepivotally connected to the respective inboard and outboard side supportbars 68, 70. The bolster support rods 218 project outwardly toward thefront of the seat 10, i.e., toward the seat cushion, to form a bolstersupport frame. The rearward face of the lumbar support panel 170includes a pair of vertical slots 220 for receiving the cross barmembers 216 therein. Each slot 220 includes a first shelf 222 forsecuring and supporting the cross bar members 216 with the seat in thenormal occupant seating position. Each slot 220 further includes asecond shelf 224 spaced from the first shelf 222 for securing andsupporting the cross bar members 216 in the impact displacementposition. Again, when a predetermined rear impact force is exerted onthe seat assembly 10 and inner occupant support frame 140, the lumbarsupport assembly 156 is forced rearwardly, behind the outer peripheralframe 66. The side support rods 210 pivot about the respective inboardand outboard side support bars 68, 70 to cradle the seat occupantbetween the outer peripheral frame 66. The slots 220 allow the cross barmembers 216 to displace from the first shelf 222 to the second shelf 224permitting rearward movement of the lumbar 156 and inner occupantsupport frame 140. Additionally the side support rods 210 also pivot andretract the bolster support rods 218 inwardly toward the center of theseat back 16 to support and retain the sides of the seat occupantagainst the inner occupant support frame 140 and between the outerperipheral frame 66. It should be appreciated that many variations ofthe inner occupant support frame and pivotal connections to the outerperipheral frame may be employed without varying from the scope of theinvention.

The present invention has been described in an illustrative manner. Itis to be understood that the terminology, which has been used, isintended to be in the nature of words of description rather than oflimitation.

Many modifications and variations of the present invention are possiblein light of the above teachings. Therefore, within the scope of theappended claims, the present invention may be practiced other than asspecifically described.

We claim:
 1. A seat assembly for supporting a seat occupant in anautomotive vehicle comprising: a seat cushion for supporting the seatoccupant on said seat assembly; a seat back extending longitudinallybetween a lower portion operatively coupled to said seat cushion and anupper portion for supporting the seat occupant in an upright position;said seat back including an outer peripheral frame member, an inneroccupant support frame operatively connected and supported by said outerperipheral frame member and movable from an occupant support position toan impact displacement position extending rearwardly of said outerperipheral frame member, said outer peripheral frame member includes aninboard side support bar spaced from an outboard side support bar andinterconnected at one end by a upper support bar to define a generallyU-shaped outer peripheral frame member, said inner occupant supportframe includes a pair of generally parallel spaced apart resilientstraps positioned between said inboard and outboard side support barsand extending between a first end adjacent said seat cushion and asecond end operatively coupled to said upper support bar of said outerperipheral frame, and a displacable connection member operativelyconnecting said inner occupant support frame and said outer peripheralframe for maintaining said inner occupant support frame in said occupantsupport position during normal seat occupant use and for providingmovement of said inner occupant support frame to said impactdisplacement position in response to a predetermined impact load exertedon said seat assembly, said displacable connection member includes alateral torsion spring element having a torsion support bar havingopposite ends and extending laterally between said opposing spaced apartside support bars and a torsion bar extending from each end of saidtorsion support bar to said respective adjacent side support bar and aspring coil interconnecting each of said torsion bars to said respectiveside support bar for providing resilient displacement of said inneroccupant support frame between said occupant support position and saidimpact displacement position.
 2. A seat assembly as set forth in claim 1wherein said first ends of said resilient straps are coupled to saidlateral torsion support bar.
 3. A seat assembly as set forth in claim 2wherein said inner occupant support frame includes a lumbar supportassembly having a planar support plate pivotally connected to saidlateral torsion support bar between said spaced apart resilient straps.4. A seat assembly as set forth in claim 3 wherein said lumbar supportassembly includes a contoured lumbar back plate operatively coupled tosaid planar support plate facing said seat cushion.
 5. A seat assemblyas set forth in claim 4 wherein said lumbar support assembly includes atleast one inflatable bladder coupled between said planar support plateand said contoured lumbar back plate for selective articulating saidlumbar back plate relative to said planar support plate.
 6. A seatassembly as set forth in claim 5 further including a head restraintassembly operatively coupled to each of said outer peripheral frame andsaid inner occupant support frame for supporting the seat occupant'shead in each of said occupant support position and said impactdisplacement position.
 7. A seat assembly as set forth in claim 6wherein said head restraint assembly includes a pair of upright headrestraint posts each pivotally coupled to said upper support bar of saidouter peripheral frame by a pivot bracket.
 8. A seat assembly as setforth in claim 7 wherein said head restraint posts extend from distalends spaced below said upper support bar and between said side supportbars to an upper arc portion to define a generally U-shaped framemember.
 9. A seat assembly as set forth in claim 8 wherein said headrestraint assembly includes an upper seat back support plate fixedlysecured to said distal ends of said head restraint posts and extendinglaterally between said side support bars for pivoting said headrestraint assembly about said upper support bar in response to saidinner occupant support frame displacing between said occupant supportposition and said impact displacement position.
 10. A seat assembly asset forth in claim 9 further including a linear recliner mechanismcoupled between said seat cushion and said seat back from selectivelyadjusting said seat back between a range of angular reclined positionsrelative to said seat cushion.
 11. A seat assembly as set forth in claim10 wherein said linear recliner mechanism includes a upper cylinderhaving a first end pivotally attached to one of said inboard andoutboard side support bar of said outer peripheral frame and a secondopen end, a lower piston having a first end telescopingly received insaid second open end of said upper cylinder and a second end pivotallyattached to said seat cushion, and a locking mechanism engagable betweensaid upper cylinder and said lower piston for locking and retaining saidlinear recliner mechanism within said range of reclined positions.
 12. Aseat assembly as set forth in claim 11 further including at least onetension spring extending between said seat back and said seat cushionadjacent said linear recliner mechanism for biasing said seat backtoward said upright position.
 13. A seat assembly for supporting a seatoccupant in an automotive vehicle comprising: a seat cushion forsupporting the seat occupant on said seat assembly; a seat backextending longitudinally between a lower portion operatively coupled tosaid seat cushion and an upper portion for supporting the seat occupantin an upright position; said seat back including an outer peripheralframe member, an inner occupant support frame operatively connected andsupported by said outer peripheral frame member and movable from anoccupant support position to an impact displacement position extendingrearwardly of said outer peripheral frame member, said outer peripheralframe member includes an inboard side support bar spaced from anoutboard side support bar and interconnected at one end by a uppersupport bar to define a generally U-shaped outer peripheral framemember, a displacable connection member operatively connecting saidinner occupant support frame and said outer peripheral frame formaintaining said inner occupant support frame in said occupant supportposition during normal seat occupant use and for providing movement ofsaid inner occupant support frame to said impact displacement positionin response to a predetermined impact load exerted on said seatassembly, said displacable connection member includes a lateral torsionspring element having a torsion support bar having opposite ends andextending laterally between said opposing spaced apart side support barsand a torsion bar extending from each end of said torsion support bar tosaid respective adjacent side support bar and a spring coilinterconnecting each of said torsion bars to said respective sidesupport bar for providing resilient displacement of said inner occupantsupport frame between said occupant support position and said impactdisplacement position, and wherein said inner occupant support frameincludes a pair of generally parallel spaced apart and longitudinallyextending wire rods positioned between said inboard and outboard sidesupport bars and extending between a first end coupled to said lateraltorsion support bar and a second end operatively coupled to said uppersupport bar of said outer peripheral frame.
 14. A seat assembly as setforth in claim 13 wherein said displaceable connection member includes acylindrical fracturable body member coupled between each of said firstends of said wire rods and said lateral torsion support bar.
 15. A seatassembly as set forth in claim 14 wherein said body member includesfirst and second elongated channels extending between opposing ends ofsaid body member for slidably receiving said first end of said wire rodand said torsion support bar respectively.
 16. A seat assembly as setforth in claim 15 wherein said body member includes a first shelfclosing a portion of said first channel from supporting said wire rodthereon adjacent one end of said body member and a second shelf closinga portion of said second channel for supporting said torsion support barthereon adjacent the opposite end of said body member defining adisplacement space therebetween.
 17. A seat assembly as set forth inclaim 16 wherein said first and second shelves are fracturable inresponse to a predetermined load force to allow ends of said wire rodsand said torsion support bar to slide along said respective first andsecond channels through said displacement space for engagement anddisplacement of said inner occupant support frame from said occupantsupport position to said impact displacement position.